Extend "Keyboard shortcuts"'s feature - Ability to call Custom function

[gunir]

If you have heard about keyconfig, this XUL addon allow you to add/modify custom hotkey, but even more it can add hotkeys that call custom function which is very powerful.

Being able to add custom function is very beneficial because:

• It will allow us to quick test new code, because we won't need to recompile and run anymore, just write a shortcut and run custom function instead.
• Very extendable, because we can add literally anything

[surapunoyousei]

Good.

[surapunoyousei]

Implemented. Will be enabled on Floorp 11.5.0